Vat dyestuffs of the indigo series and process of making same.



earn eras rr GADIENT ENGI, OF BASEL, SWITZERLAND, ASSIGNOR TO SOCIETY OF CHEMICAL INDUSTRY IN BASLE, 0F BASEL, SWITZERLAND.

VAT DYESTUFFS OF THE INDIGO SERIES AND PROCEBSl 9F MAKING SAME.

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7 Specification of Letters Eats-mt.

-To all whom it may concern:

Be it known that I, G DIENTENGI, doctor of philosophy and chemist, a citizen of the Vat Dyestuffs of the Indigo Series and Process of Making Same, of which the following is a full, clear, and exact specification.

In the United States, Letters Patent No. 997766 datedJuly 11th 1911 are described halogenated vat dyestufls obtained by halogenating the condensation products described in the United States Letters Patent No. 994988 dated June 13th 1911, resulting from the action of the haloids of aromatic acids on indigo compounds. I- have now found that the said halogenate'd'vat-dyestuds, which dye .animal andvegetable fibers from an alkaline vat pure greenish yellow tints, can be transformed into new reddish yellow to orange yellow vat dye-stuffs, by treating the same with reduced agents, especially sulfhydrates, hydrosulfites and the like, in absence of caustic alkalis and preferably in presence of an organic medium mixable with water.

Exam le I: 20 parts of the dyestufi' ;.obtained fiy brominating the condensation product of indigo with benZoyl-chlorid are suspended in a finely pulverized state in 200 parts of alcohol and heated to'ebullition in an apparatus provided with a reflux cooler and hereafter parts of a solution of sodium sulfhydrate of 48 per cent. NaHS are added. The mixture is boiled for about 1 to 2 hours and poured slowly into water of 50 to 60 C.; the thus separating dyestufi' is filtered off. Dried the new dyestufi' forms a deep orange powder, scarcely soluble in cold alcohol and difiicultly-soluble in hot alcohol. In cold nitrobenzene it dissolves easily with a yellow-brown coloration. Its solution in concentrated sulfuric acidhas an intense red-brown color and yields by addition of water a yellow-orange precipitate. Fuming sulfuric acid dissolves it with a deep brown coloration; hereby a partial sulfonation of the product takes place, the solution diluted with ice-water showing-an intense yellow coloration. By treating the dyestuff with hydrosulfite aiid caustic alkali a wine-red vat is obtained which dyes vegetable and animal fibers reddish yellow tints-of excellent fastness. After exposure to air the so obtained dyeings are subjected to a treatment with'hot baths (for instance a soap bath for cot-ton and hot dilute acids for W001), where by the tints become some more pure and more vivid. The same effect can be pro Patentedflct. '7. 19118. Application filed May 8, 1912. Serial No. 695,880.

.duced by treating the dyeings with chlorin.

- Example II: 10 parts of the brominated condensation product specified in Example I, 100 parts of alcohol, 10 parts of sodium hydrosulfite and 12 parts of water are boiled togetherfor 5 to 6 hours. After cooling, the

mass is filtered and the residue remaining on.

the filteris washed at first with alcohol and afterward with water and finally dried. The dyestufi thus obtained constitutes an orange-brown powder dyeing textile fibers from an alkaline ,vat reddish yellow tints.

Instead of alcohol any other organic liquid mixable with water can be employed in the foregoing examples and the sodium sulfhydrate or hydrosulfite can be replaced by any other reducing agent having the same action.

. What I claim is: I

1. The described process for the manufacture of new reddish yellow vat dyestuffs of theindigoseries' consisting in treating a halogenated derivative of the condensation product resulting from a haloid of an aromatic acid and an indigo compound with reducing agents'in absence of caustic alkalis.

2. The described process for the manufacture of new reddish yellowvat dyestuifs of the indigo series consisting in treating a halogenated derivative of the condensation product resulting from a haloid of an aromatic acid and an indigo compound, with reducing agents in absence of caustic alkalis and in presence of an organic diluent mixable with water.

3. Asnew products the vat dyestuffs of the indigo series obtained by reducing the halogenated derivatives of the condensation products resulting from the haloids of arol matic acids'and. indigo compounds, in absence of caustic alkalis forming in dry state orange to orange-brown powders insoluble in water, difficultly soluble in hot alcohol,

lutions from which, on addition of ice-water,

the unaltered dyestufi' is precipitated in the form of yellowish orange flakes, yielding by treating withicaustic alkali and hydrosulfite 5 a wine-red colored vat, from which textile Witnesses:

fibers are dyed in reddish yellow shades fast GEO. GIFFORD,

to washing, light and chlorin. AMAND BITTER.

In witness whereof Iha've hereunto signed my name this'26th day of April 19l2,-in the presence of two subscribingwitnesses.

GADIEN'I ENGI.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patentsk Washington, D. G. 

